With Delanie Walker sidelined by a knee injury Sunday, the 49ers signed have signed two tight ends: Gijon Robinson (Indianapolis Colts; Missouri Western) and Joe Sawyer (Southwestern Oklahoma). Guard Garrett Chisolm was released, and the 49ers roster is now maxed out at 90.

Both Robinson and Sawyer were on the field for the start of Monday’s practice. Several key players were not, however: defensive lineman Isaac Sopoaga; linebackers Aldon Smith, Ahmad Brooks, Tavares Gooden and Cam Johnson; tight end Nate Byham; and Walker.

Robinson, who signed a one-year contract, played the past three seasons with the Colts. He and Sawyer (three-year deal) add depth to a position depleted by the loss of Walker and Byham.

Coach Jim Harbaugh said Sunday he believed the 49ers “dodged another bullet” in terms of the severity of Walker’s injury. Byham has been out the past week as he tries returning from an ACL tear that sidelined him last season.

Smith, who bruised his right hip in Friday’s exhibition opener, will miss time this week but is not a long-term concern, defensive coordinator Vic Fangio said earlier today.

The status of Sopoaga, Brooks and Gooden will be updated when more information is gathered.

I’d say that practice squad is where the Garbage Man will find himself. With Dobbs catching the ball, the Niners may go with just two TEs and cut Byham, too. But next year with Walker as a FA, things will be more promising for the G Man, unless the Colts get him for adding to Luck’s stable of receivers.